1. Field of the Invention
The present invention relates generally to braces for secure engagement of body parts with surfaces such as the interiors of vehicles, and the like, particularly watercraft. And, the invention relates more specifically to padded braces used in plastic and fiberglass kayaks and like watercraft for secure engagement of the user with the watercraft, and for permitting the user to apply force against portions of the watercraft to control the watercraft's movement and performance.
In the sport of kayaking, and especially in the subcategory of that sport practiced in rushing rivers commonly referred to as "whitewater" kayaking, it is important that the user of the kayak have a snug, yet comfortable, fit in the watercraft's cockpit. A good fit at the buttocks, lower back hips, thighs, knees and feet is critical to proper control of the craft's roll, pitch and yaw. To achieve the best fit, it has been common practice to fashion a custom seating area out of blocks of dense, resilient, closed-cell foam, trimming and shaving down the surfaces to match the contours of the owner's physique until the seat grasps the user's buttocks and thighs snugly. The feet are normally placed against a pair of foot pads, pegs, or a bulkhead wall, adjustable fore and aft to a point which, optimally, permits the user's knees and the adjacent, distal portion of the user's thighs to be splayed outward and wedged against the side walls of the hull, under those portions of the foredeck that extend rearward to the right and left of the cockpit. Reference to the distal portion of the user's thigh is intended to direct attention to that portion of the thigh farthest from the pelvis.
The points where the knees and distal thigh portions wedge against the side walls and up under the left and right rearward foredeck portions need to be fashioned for secure, comfortable engagement of the knees and distal thighs with the craft. Indeed, those points of engagement are extremely important, because it is the user's application of force against those points with the knees and distal thighs which yields precise edge control, i.e. the ability to raise one side edge of the craft higher than the other in reference to the water line. Edge control is essential to efficient turning, lateral movement and cross-current travel, as well as in righting the craft with the "Eskimo roll" maneuver after a flip. Thus, simply providing padding for distal thigh-knee force in a horizontally outward direction against the hull's outer walls, i.e. perpendicularly away from the central, longitudinal axis of the kayak, as was done in the past, is not sufficient. Force also often needs to be applied in an upward direction, i.e. vertically under the left or right rearward foredeck portions. Thus, the undersides of the deck in these side areas have been found to need padding, as well.
Further, many maneuvers require means to use the distal thigh and knee in drawing the hull wall in an inward direction, i.e. horizontally toward the central, longitudinal axis of the kayak. Different sculpted, overhanging foam pad configurations, straps, and other devices have been experimented-with in attempting to give kayakers more ability to use the knees and distal thighs to draw the hull wall toward the center of the craft. But, modernly, it has become standard practice for whitewater kayak manufacturers to form the left and right rearward portions of the foredeck, flanking the forward end of the cockpit, to wrap over the distal thigh and knee. In such constructions, short, wing-like panels generally referred to as "knee braces" depend rigidly from the inner edges of the cockpit rim to retain and receive force from the inner anterior surfaces of the distal thigh-knee region of each of the user's legs. Alternatively, several current manufacturers mold such rigid, depending, wing-like, knee braces into various types of reinforcing "brace plates." Such brace plates are generally C-shaped in plan view, four to ten inches or so wide, and adapted to be fastened to the underside of a kayak's deck, surrounding the front of the cockpit and its forward left and right sides. Examples of such C-shaped brace plates are found in whitewater kayaks currently sold by Perception, Wave Sport, and Dagger. However, because these rigid structural knee brace components are designed in a "one size fits all" fashion, they pose continuing problems in custom fitting kayaks to the user.
Despite the rigid structural components of knee braces being part of most modern mass-manufactured kayaks, they pose continuing problems in custom-fitting a kayak to a particular user. Due to the great variation in leg lengths and thicknesses among kayakers, for the best fit and control it has been common practice to line the entire area within each knee brace with dense, resilient, closed-cell foam and then to sculpt the surfaces to receive the anterior face and the anterior portions of the inner and outer side faces of the knee and adjacent distal end of the thigh of the intended user. This is a time-consuming, expensive process. And, for some unusual-sized kayakers, no amount of custom foam work is adequate; the position of the fixed knee brace and/or the limited room provided therewithin make a comfortable fit impossible. Further, once a good fit is achieved with custom-sculpted foam, presumably for the kayak's owner, it becomes very difficult for a person with a different body shape or size to fit, use and properly control the craft in comfort.
Thus, these problems with knee brace fit contribute to several persistent barriers to flexibility and versatility of equipment use in the sport of whitewater kayaking. First, they make it more difficult for the prospective purchaser of a new kayak to field-test the craft under conditions which permit full use of all of its control surfaces. Second, the purchaser of a used kayak must endure the discomfort of a less-than-optimum fit and attendant lack of performance, or otherwise be saddled with the bother and expense of resculpting the knee brace portions of the craft. Third, knee brace fit problems caused by permanent pad installations prevent paddling companions from swapping kayaks and trying out different hull sizes and constructions, thus unnecessarily limiting the range of experience one might otherwise enjoy if knee and distal thigh fit were not so critical to kayak comfort and control.
Recently, two well-known whitewater kayak manufacturing companies have introduced adjustable knee brace systems. WildWasser Sport USA, Inc. of Boulder, Colo. offers adjustable knee braces in its Prijon line of boats, and Impex International of Bellport, N.Y. offers adjustable knee braces in its Pyranha line. However, both the Prijon and the Pyranha systems only permit the knee brace to be adjusted along a line parallel with the kayak's central, longitudinal axis. Further, the depending, wing-like, rigid, knee and distal thigh-engaging panels used in these unidimensionally-adjustable systems are fixed at angles divergent from the kayak's seat toward its bow, but these angles are set for the "average-sized" kayaker. Thus, although permitting some adjustment for comfort and control, and eliminating the need for some of the custom foam sculpting, analyses of the differences in geometry of human bodies of different sizes, supported by empirical studies, leads to the inevitable conclusion that the Prijon and Pyranha unidimensionally-adjustable knee brace systems do not address all of the needs for a good, adjustable distal thigh-knee fit. Indeed, it can be readily appreciated that the inside thigh surfaces of the fully-splayed legs of a short-statured kayaker reside at an angle much more divergent from the kayak's longitudinal axis than those of a tall, long-legged kayaker. Thus, the rearward edge of a fixed-angle, longitudinally-adjustable knee brace panel, when driven fully rearward in the cockpit, will tend to dig into the distal thigh of a short-legged kayaker; and, the forward edge thereof will tend to dig into the knee of a long-legged kayaker when driven fully forward.
Another aspect of human geometry not addressed by the Prijon and Pyranha knee braces is that, in the context of conventionally-shaped whitewater kayak, the longer a kayaker's legs, the closer together the knees must be. That is because a kayak, in plan view, is tapered from cockpit to bow. Thus, the farther forward a knee brace is moved along an adjustment track fixed parallel to a kayak's longitudinal axis, the less room is left laterally between the depending, rigid, knee brace panel and the hull side wall. The longest-legged kayakers, therefore, have each knee pinched into its respective brace. Of course, this is most uncomfortable for long-legged kayakers whose legs are very thick, as well.
Yet another need not addressed by the conventional construction of knee braces is in adjustment of the height of the brace over the knee of the kayaker. Knee brace height is normally adjusted by starting with a thick block of foam and shaving it down to achieve the correct height. Generally, more foam is needed for high-decked kayaks, and less foam is needed for those with low decks. But, once set, the fit cannot be temporarily adjusted to fit another kayaker.
In attempts to permit multiple, different-sized kayakers the use the same kayak without completely re-sculpting the cockpit, some kayak renters, trip outfitters and the like, line some of the inside surfaces of the kayak cockpit with patches of fastening fabric such as Velcro, and then employ a collection of Velcro-backed knee, hip and lower back pads of different shapes, sizes and thicknesses to approximate a custom fit. This approach has some advantages, but the considerable stresses on some of these pads during a vigorous whitewater workout tend to tear the mating Velcro patches apart, causing the pad to be separated from the cockpit shell and, ultimately, causing loss of control. Further, during a quick exit from a kayak in whitewater conditions, such pads are easily torn loose and lost. However, one of the most difficult aspects of using mating Velcro patches for pad placement is that they provide no mechanism for fine incremental adjustments. Once placed in position, if the fit is not optimum, slight adjustments are not possible. The pad and its Velcro patch must be completely disengaged from the Velcro patch in the cockpit before being moved and replaced. This is quite difficult and can become very time consuming, because it requires that the kayaker being fitted continually climb in and out of the cockpit for readjustment.
Adjustable knee-thigh braces employed in a related class of craft known as "sit-on-top" kayaks, i.e. those having a completely closed hull, are also known. One example is shown in French Patent No. 2,641,757 issued to Rerolle in 1990 wherein knee braces ("stop surfaces 5,6") project laterally from a hump-shaped forward, central hull astride which the kayaker sits. However, Rerolle's knee braces appear adjustable fore and aft, at best.
U.S. Pat. No. 4,589,365 issued to Masters in 1986 shows longitudinally-adjustable thigh braces ("wing members" 70 and 72) for a sit-on-top kayak. However, Masters does not suggest these braces should be adjustable in any other plane or direction.
French Patent No. 2,673,416 issued to Brissaud in 1992 shows another sit-on-top with thigh braces ("overhangs" 1 and 2). Brissaud's braces may be either fixed, as shown in an embodiment where they are integral with the rest of the closed-hulled craft, or adjustable, as shown in another embodiment where they comprise separate structures. However, adjustability appears to be limited to the longitudinal direction.
Thus, it appears that a need exists for a kayak knee brace which is adjustable both longitudinally and laterally. And, optimally, the brace's depending panel should lie flush against the inside and anterior surfaces of the user's knee and distal thigh, whether the user has short, wide-splayed legs, or long, less-divergent legs. It would also be advantageous if such a kayak knee brace were easy to position and reposition securely by a lower-skilled kayak cockpit outfitter, thereby reducing the cost of fitting new and used boats to new users, and making it easier for paddling companions to make temporary cockpit outfitting adjustments for the purpose of borrowing one anothers' boats.